The urgent question along the polluted Gulf of Mexico: How bad will this get?

No one knows, but with each day that the leaking oil well a mile below the surface remains uncapped, scientists and energy industry observers are imagining outcomes that range from bad to worse to worst, with some forecasting a calamity of historic proportions. Executives from oil giant BP and other energy companies, meanwhile, shared their own worst-case scenario in a Capitol Hill meeting with lawmakers, saying that if they fail to close the well,the spill could increase from an estimated 5,000 barrels a day to 40,000 barrels or possibly even 60,000 barrels.

Three scientists in separate interviews Tuesday said the gulf’s “loop current,” a powerful conveyor belt that extends about 3,000 feet deep, will almost surely take the oil down through the eastern gulf to the Straits of Florida, a week-long trip, roughly. The oil would then hang a sharp left, riding the Florida Current past the Keys and north again, directly into the Gulf Stream, which could carry it within spitting distance of Palm Beach and up the East Coast to Cape Hatteras, N.C.

For the moment, the oil flowing from the blown-out well in what the industry calls Mississippi Canyon Block 252 is still many miles north of the loop current. A three-day forecast by the National Oceanographic and Atmospheric Administration does not show the oil and the current crossing paths. But Robert Weisberg, an oceanographer at the University of South Florida who has been monitoring the situation, said a new filament of the current is reaching toward the oil slick.

“The loop current is actually going to the oil, versus the oil going to the loop current,” Weisberg said.

The crisis in the gulf is shot through with guesses, rough estimates and murky figures. Whether the oil blows onshore depends on fickle winds. This oil slick has been elusive and enigmatic, lurking off the coast of Louisiana for many days as if choosing its moment of attack. It has changed sizes: In rough, churning seas, the visible slick at the surface has shrunk in recent days.